In 1967 Garfinkel and Bittner were investigating good organizational reasons for bad clinic records, demonstrating how the reading of such records as sociological data should be reported to the understanding of their production's practical contingencies and to the situated circumstances of their use. This seminal paper opened new avenues of research related to the study of records in various professional contexts and of their transformation, to the development of praxiological approaches to practical and professional texts, or to the study of historical documents and archives. To contribute to this ethnomethodological strand of research, I propose a case-study of artworks' records management at the museum, investigated as a perspicuous site to reflect upon how artworks are experienced, apprehended and defined in the institutional ordinary business. Drawing on observations and materials collected at the French National Museum of Modern Art, I study records' careers (how they are produced, used and transformed by museum's members) and describe their material and organizational properties, by giving a close look at some elements (initial artworks' descriptions, installation instructions and confidential correspondence). More particularly, I focus on one distinctive property of some records: their thickness, investigated as a scheme of interpretation of the situated features of documentation work. By reading artworks' records as local collective practices of assemblage, disruption and reconfiguration of pieces of documentation, I demonstrate that what is documented in this process is not only the artwork: it is also the collective work of working with artworks, dealt with as ongoing achievements of institutional practices.